Machine for bending metal strips



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MACHINE FOR BENDING METAL STRIPS Filed Dec. 16, 1952 3 Sheets-Sheet 3 Fig. 3

I i 11 1O 11 V I f w W In were 7%) df/vra United States Patent 2,717,021 ORBENDING ETAL, SI I Z Uno Bernhard Rylander, Arsta, Stockholm, Sweden, as-

signor to Svenska Skofabrikantforeningen, Stockholm, Sweden, acgrporationofisweden Application December 16, 1952, Serial'No. 326,201

3 Claims. (CI. 153 4;

The, invention. relates to. improvements in a machine for bending metal strips exactly to a predetermined contour, such bent strips being required for instance in producing cutting diesfor cutting blanks from leather, skin, fabrics, plastics, paper or the like.

In producing dies for cutting leather etc. it is conventional first to bend a metal strip to the desired contour and then to harden and temper it, whereupon the edge is ground. In the last few years it has been proposed to harden, temper and grind the strips before their bending. Of course, such a manner of action is more difficult to carry out but has proved to be fully justified in that it brings about certain advantages. Among other things it is possible to obtain the desired contour exactly, as no deformation occurs as a result of a subsequent treatment in heat. Also it is simpler to grind the strip when in a straight condition. However, to make it possible to utilize the advantages inherent in this method it is desired to have a machine easily operable to perform bending of such hardened metal strips.

The object of the invention is to provide a machine by which metal strips may be bent exactly to the desired contours. Another object is to provide a machine of the type referred to in which the bending by automatically operating means may be controlled by manually operated means, which latter may also be used for bending the material and especially for final adjusting of bendmgs.

These and further features of the invention will be more fully described hereinafter with reference to the annexed drawings in which:

Figure 1 is a vertical section of the machine according to the invention,

Figure 2 is a view along the line IIII in Figure 1, partly in section, and

Figure 3 is a section along the line IIIIII in Fgure 1.

In the drawings, 4 designates a frame serving to carry the operative elements of the machine. The front and rear ends of said frame 4 have legs 5 and 6 respectively of difierent lengths and projecting perpendicularly downwards to support the frame on a table 7 in a position somewhat inclined forwardly. The frame has a longitudinal guide slot in which two slides 8 and 9 are guided. Said slides have in section the shape of a T turned upside down and are kept in the slot by plates 10 fixed to the frame by bolts 11 at both sides of the slot and overlapping the longitudinal edge portions of the slides. The upper sides of the two plates together form a table and are in the same plane as the upper surfaces of the slides.

The two slides 8 and 9 carry cooperating dies 12 and 13 projecting over said plane of the two plates 10. The dies have projecting portions 14 inserted in corresponding holes in the slides near their opposite ends. The upper portions of said holes are continued by longitudinal recesses in the slides. Stay members 15 are placed in the recesses and tightened with bolts 16 to the dies and held in position by the hands.

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h reciproeatina amie tz hem ad elr ta eatee y h i e a cor ng, sg ha axaa sa 1 9, s ielplates 19 are Placed in aarallel. a atiet s etedis aasa from each other in the'direction of the slide9 and are fixed to the rear leg 6 of the frame 4. Said plates have two horizontal borings of large diameter arranged in alignment to each other, and two disks 20 are rotatably journalled in these borings. Each disk has a peripherical flange 21 contacting the inside of the corresponding plate around the boring and the disks are firmly connected to each other by means of a segment-shaped element 22. A long rod 23 has one end fixed to said connecting element 22 and extends downwards under the table 7. The other end of the rod 23 (not shown in the drawings) is located somewhat above the floor and carries a pedal which is to be actuated by the foot to rock the rod and 7 thereby to turn the disk assembly.

A shaft 24 is journalled in ball bearings 25 mounted eccentrically in the disks 20. An eccentric 26 is fixed on the shaft in the space between the disks, and the outer end of the shaft carries a pulley 27 which is to be connected to a driving motor not shown. One end of a connecting rod 28 is by means of a ball bearing 29 journalled on the eccentric 26 which consists of a cylindrical disk eccentrically fixed on the driving shaft 24. The other end of the connecting rod 28 is pivotally connected to the rear end of the slide 9 carrying the male die 13.

In bending a strip by means of the dies, the mechanism described above is operated as follows. A pattern showing the contour which is to be given to the strip by the bending operation is fixed to one of the longitudinal edges of the strip and the latter is introduced between The shaft 24 is driven by the motor whereby the eccentric causes the reciprocating movement of the male die 13. Simultaneously, the disks 20 supporting the shaft 24 may be turned more or less by actuating the pedal on the rod 23, so that the die 13 is pressed more or less powerfully against the strip to be bent. In this way the operator has in his hand to control the bending operation exactly. When the bending is almost completed, a final fine adjustment may be done in that the driving motor is stopped or disconnected and the reciprocation of the die 13 is effected exclusively by rocking the rod 23 by means of the foot.

It is obvious that the combination of automatic and manual operation according to the invention may be obtained also by other means than those heerinbefore described. The essential thing is that the bearings for the eccentric shaft may be moved manually towards and from the stationary die, so that the pressing operation may be effectively controlled.

For instance, .the rocking rod 23 may be a doublearmed lever pivotally mounted between the plates 19, and its upper end may be fork-shaped to support the eccentric shaft 24.

Other embodiments are also possible within the scope of the invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A machine for bending metal strips, comprising in combination two cooperating dies, eccentric means including a shaft for reciprocating one of said dies toward and from the other die which is stationary, bearings for the eccentric means shaft arranged eccentrically in a support pivotable around an axis parallel to said eccentric means shaft, driving means for the eccentric means and manually operated means for pivoting said support.

2. A machine for bending metal strips, comprising in combination two cooperating dies, eccentric means including a shaft for reciprocating one of said dies toward and from the other die which is stationary, bearings for the eccentric means shaft arranged eccentrically in a support pivotable around an axis parallel to said eccentric means shaft, driving means for the eccentric means, and a rod having one end fixed to the pivotable support, while its other end extends downwards and is provided with a pedal to be actuated by the foot to rock the rod and thereby to pivot said support.

3. A machine for bending metal strips, comprising, in combination, two cooperating dies, eccentric means including a shaft for reciprocating one of said dies toward and from the other die which is stationary, bearings for the eccentric means shaft arranged eccentrically in a support pivotable around an axis parallel to said eccentric means shaft, driving means for the eccentric means and manually operated means for pivoting said support, said manually operated means including a lever having one end secured to the pivotable support.

References Cited in the file of this patent UNITED STATES PATENTS 722,149 Schott Mar. 3, 1903 950,594 Condict Mar. 1, 1910 953,768 Sutherland Apr. 5, 1910 2,222,095 Van Dusen Nov. 19, 1940 2,256,908 Rafter Sept. 23, 1941 

